# U-boot prompt not visible

**URL:** <https://hub.mender.io/t/u-boot-prompt-not-visible/2265>\
**Category:** General Discussions\
**Tags:** yocto, raspberrypi-cm3, warrior, u-boot\
**Created:** [July 30, 2020, 2:56pm UTC](https://hub.mender.io/t/u-boot-prompt-not-visible/2265 "2020-07-30T14:56:58Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![thesillywhat](https://avatars.discourse-cdn.com/v4/letter/t/57b2e6/32.png) [@thesillywhat](https://hub.mender.io/u/thesillywhat)\
**Post date:** [July 30, 2020, 2:56pm UTC](https://hub.mender.io/t/u-boot-prompt-not-visible/2265/1 "2020-07-30T14:56:58Z")

</div>

Hello,

I am currently having an issue where if I change the config.txt to enable certain overlays, u-boot prompt is not visible anymore.

I am using raspberrypi-cm3 with yocto warrior branch. I created two raspberry-pi images using this link  
[https://hub.mender.io/t/raspberry-pi-3-model-b-b/57/28](https://hub.mender.io/t/raspberry-pi-3-model-b-b/57/28)

1. one image with my config.txt changes(u-boot prompt not visible)
2. one image with no changes (u-boot prompt visible)

```auto
   framebuffer_height=600
    framebuffer_width=1024
    display_rotate=0
    #dtoverlay=vc4-kms-v3d
    dtoverlay=dpi24 
    hdmi_ignore_edid=0xa5000080
    enable_dpi_lcd=1
    dtoverlay=pwm,pin=40
    dtoverlay=i2c-rtc-gpio,pcf8523,i2c_gpio_sda=44,i2c_gpio_scl=45,i2c_gpio_delay_us=2
    display_default_lcd=1
    dpi_group=2
    dpi_mode=87
    dpi_output_format=0x6f007
    hdmi_timings=1024 0 60 4 60 600 0 10 4 10 0 0 0 60 0 43000000 5

```

I had to make changes to my config.txt mainly to accommodate my display screen. It is connected to the DPI pins

How do I change u-boot configuration to allow my LVDS display settings?  
I think that is the reason why u-boot prompt is not getting displayed  
Edit 1: Added new information

---

<div class="post-metadata">

**Author:** ![mirzak](https://yyz2.discourse-cdn.com/flex036/user_avatar/hub.mender.io/mirzak/32/2056_2.png) [@mirzak](https://hub.mender.io/u/mirzak)\
**Post date:** [July 31, 2020, 12:42pm UTC](https://hub.mender.io/t/u-boot-prompt-not-visible/2265/2 "2020-07-31T12:42:29Z")

</div>

> [@thesillywhat](#):
>
> How do I change u-boot configuration to allow my LVDS display settings?

This you probably need to do in the U-Boot sources in either the header configuration file (rpi.h), board file (rpi.c) or maybe even in the device tree in the U-Boot for the RPi.